From the genesis of modernism at the start of the 20th century to the present day, one of the main concerns in the designing of buildings is that a maximum amount of natural light is admitted. From fairly conventional structural inner cores in concrete and steel—which are constructed from the bottom up—to the more complex variants, these constructions allow in buildings maximum glazing of the facades via the overhang principle. The rapid development of the curtain wall and associated glass technology is obviously a logical consequence of this. To this day, there is huge demand in construction for ever larger glass surfaces in ever more complex forms and assemblies.
The problem of the format of the—assembled or non-assembled—glass parts to be used is of course linked to, inter alia, the problem of the wind load to be accommodated and the energy permeability of the glass. Despite the multiplicity of high-technological glass assembly solutions, the placing of a manipulable external sun protection system at the level of the facades on which the sun shines remains to this day the most efficient manner to correctly control the irradiation heat in order thus to prevent the greenhouse effect indoors.
Nowadays, energy-saving building is highly topical. More than ever before, architects and consultants have been found to be convinced that an excessive amount of energy, which still enters via glass panels oriented toward the sun, may no longer be cooled via cooling systems which waste energy. The development of the external sun protection systems would appear partly to allow for this defect. The sun protection systems on offer are becoming more and more diverse in type and form and are at the same time becoming more manipulable.
Most of what is commercially available and, in other words, is also used is in the form of vertical or horizontal awning systems, blinds and curtains consisting of slats and which are deformable in their entirety. Wall entities of this type are deformed by the pivoting or tilting, manually or by means of an actuator, of these slats which are mounted in a frame or a shutter. This is carried out in all cases using intermediate hinge points and guide rails.
There are also moving systems which are already automated, wherein parts of walls and/or roofs can be opened or closed. Intermediate hinges, pivots and guide rails allow complex forms to be generated during the movement of these components.
Thus, for example, the Expanding Retreat House project, which was developed within the context of Smart Geometry—Workshop & Conference, New York, January 2007, comprises a system of mechanical blinds which serve in their closed position as a secondary weather and fire casing and which are folded up in their open position to form sun protection for the windows. The blinds are pushed up or down (using a jack or hydraulically) by means of a force. Depending on the location of the buckling point (or hinge point), a specific deformation of the blind will occur. The starting point of one blind and its buckling point can differ from those of an adjacent blind, as a result of which a specific aesthetic effect is obtained.
However, the drawback of this system is that it is limited in its manipulability, since the blinds can be moved merely in one way, namely at the level of the buckling or hinge point of the blind.
WO 2007/093285 discloses a deformable free-standing wall system which is provided with a light central core system sandwiched between two outermost lining plates. Parallel incisions over the complete height on one or on both sides of the wall allow the wall entity to curve and to be made to stand fairly upright. The wall can thus be completely rolled up in order to be transported and subsequently erected in accordance with a specific curve.
Also known is a wall system consisting of a number of small plates which, activated by a large number of actuators, are movable, referred to as the Aegis Hyposurface. The movement of these plates is activated by the deformation of a rear intermediate piece which connects the triangular plates at the corners, and which in this way allows the plates to move and/or hinge separately from one another. This wall system combines information technology with a physical variable appearance. The screen is said to be dynamic. A large number of patterns and shapes in the wall system is possible. However, the system remains primarily a design approach, since it strives for an aesthetic view which otherwise solves next to no problem of building physics.
The article “The development of the flexible louver” by BUNA, T. (Martin Marietta Aerospace, Denver, Colo.) describes the use of flexible blinds as a thermal control instrument. This system was developed from space travel. The slats can be activated, placed in a convex or concave manner, by one or more actuators. As a result of the specific manner of reflection, radiation can no longer enter as would be the case in conventional blinds. In this case, the slat system forms part of a micro-technological entity suitable for space travel. However, this system is completely inappropriate for building applications on earth.